The present invention relates to a roofing disc to be utilized with a fastener and more particularly to a disc to be utilized in the securing of insulation or roof membranes to a roof deck structure.
It is quite common in the roofing industry for new roof installation to utilize wood, metal, structural, cement fiber and lightweight concrete decks to which is secured a layer of insulation which may in turn be covered by a roof membrane.
These layers are secured to each other by use of an elongated fastener that typically has an enlarged disc-shaped head which serves as a stress plate. When utilized with insulation having a lightweight brittle-type skin, it was necessary to compress the insulation board when installing the fastener in order to determine that the fastener was completely tightened. When approaching this point, it was very possible to strip out the underlying deck material and cause the fastener to lose valuable holding power or pull-out resistance. It was also possible that when the fastener was tightened to this extent that the edge of the fastener head could cut or break through the insulation skin which would also lead to less pull over resistance for the insulation.
Another situation frequently encountered in the roofing industry, is that in high winds the roofing membranes would have a tendency to tear and slide out from beneath the stress plate. This is referred to by the industry as side tear.
With other insulating materials that utilize cured rubber membranes, the rubbery material would have a tendency to pull or wrinkle when the fastener came into contact with it as it was rotated into the roofing structure. This wrinkling is unacceptable especially in a situation where the membrane must be seamed to an adjoining membrane.